refactor(frontend): extract reusable hooks and page helper modules

vite-frontend/src/pages/forward/order.ts

@@ -0,0 +1,47 @@
+import { loadStoredOrder } from "@/utils/order-storage";
+
+export interface ForwardOrderItem {
+  id: number;
+  userId?: number;
+  inx?: number;
+}
+
+export const FORWARD_ORDER_KEY = "forward-order";
+
+export const getUserScopedForwards = <T extends ForwardOrderItem>(
+  forwards: T[],
+  currentUserId: number | null,
+): T[] => {
+  if (currentUserId === null) {
+    return forwards;
+  }
+
+  return forwards.filter((item) => item.userId === currentUserId);
+};
+
+export const buildForwardOrder = <T extends ForwardOrderItem>(
+  forwards: T[],
+  currentUserId: number | null,
+): { order: number[]; fromDatabase: boolean } => {
+  const userForwards = getUserScopedForwards(forwards, currentUserId);
+
+  const hasDbOrdering = userForwards.some(
+    (item) => item.inx !== undefined && item.inx !== 0,
+  );
+
+  if (hasDbOrdering) {
+    const dbOrder = [...userForwards]
+      .sort((a, b) => (a.inx ?? 0) - (b.inx ?? 0))
+      .map((item) => item.id);
+
+    return { order: dbOrder, fromDatabase: true };
+  }
+
+  return {
+    order: loadStoredOrder(
+      FORWARD_ORDER_KEY,
+      userForwards.map((item) => item.id),
+    ),
+    fromDatabase: false,
+  };
+};